Material for use in the manufacture of glass.



;To all whom it may concern:

UNITED STATES PATENT "OFFICE.

nit-onus c'onunnrus SULLIVAN, or oonunre, NEW Yonx.

' MA'rEnIAL ron Usn' IN THE mnum mm or GLASS.

990,60 No Drawing.

Be it-known that I, EUGENE Counnnros SIZLLIVAX, a citizen of the United States,

residing at Corning, county of Steuben, and State of New York, have invented certain new and useful Improvements in Materials for Use'in the Manufacture of Glass; and I; do hereby declare the following to be afuIhclear, and exactdescription of the invention, such as will enable others skilled in the art. to which it appertains to make and use the same.

. In the present practice of the manufac ture of lead glass,the lead is uniformly introduced into the glass as lead oxid,-either litharge' or ininifum. These are expensive materials and diflicult to handle without the formation of dust and consequent injury to the health of the workmen. .Some other lead salts have been proposed as substitutes for these oxids, such as lead sulfate,

carrying out said method, the native lead sulfid ore (galena) is first purified by washing', jigging or other mechanical or chemical operatlons, so as to remove from it, in particular, any .iron minerals associated with it. The purified lead sulfid is then ,mixed, in proper proportions, with a difiicultly fusible material (for instance a sub stance containing combined or uncombined silica, suchas ure sand, or feldspar) of such quality as, 1s suitable for glass making.

A mixture of the l'ead sulfid and silica (or of the lead sulfid and fields ar)', both of the required urity for a lea lass charge (exceptingtlie sulfur preseng, is then roasted in any suitable form of roasting furnace, at the speed and temperature best adapted for removing the sulfur most completely from the roasted material. I have found, for instance, that by hand roasting a mixture of three parts by weight of pure sand to one part by weight of galena in a reverberatory furnace, at a temperature ris- Specification of Letters Patent.

that a suitable mixture for the Patented Apr. 25, 191i.

Application filed July 12, 1909 Serial No. 507,104. 4

ing to between 900 and 1000' degrees centigrade, and allowing the roasting material to remaln about. twentyfour hours in the furnace,,w1th stirring at intervals of one hour, the sulfur remaining has been reduced to 0.05 per cent, furnishing a practically pure lead product, pure enough to satisfy the very exacting requirements of the lead glass maker. The lead-bearing substance, which I thus produce is of a. granular, non-dusty and sintered form. The small grains appear tobe almost entirely of quartz, with a more or less irregularly distributed pebble-dash surface of lead silicate. Some of the grains carry more of silicate than others and the silicate shades into-the quartz rather-gradually, showing all gradations of. concentration. At the outer surface, the silicate is apparently a, pure component judging from its refractive index, and the roasted productas a whole appears clean, and sufficiently uniform'fo'r the purposes intended.

Thelad-bearing substance, produced in accordance with the invention, is mixed with any other material a-ppropriato to lead glass manufacture and the mixture is then fused down to lead glass. I have found urpose may be compounded of say the sintered lead product '40 pounds, pearlash 6% pounds,

soda pounds and niter 1 pound.

In compounding and thereafter handling,

storing ortransporting from one art of the works to another a batch ma. e with lead silicate, the mixture is found to take on and muintain greater uniformit of distribution of the ingredients throug out-the mass than when litharge is empldyedtfor thc reason, that the specific gravitiy; of the lead silicate more nearly correspon' tothat of the remaining constituents.

A further advantage to be gained by the use of lead silicate in the manufacture of lead glass is that. it is free from metallic lead, which'is present up to one-half of one per cent. and more'even in the best corntnercial litharge, and also to some extentun minium. This metallic lead tends to give the glass it tends to shorten the life of the glass- 165 a darker color, and, furthermore,

melting pot. by eating through the pot wall. a

In manufacturing lead glass containing (used as lime, limestone or be mixed with the silica and thus participate in the roastlime, th e lime gypsum) may lead sulfid and gypsum alone may be mixed with the lead ing operation. Or the lime, limestone or sulfid and roasted therewith, the silicabeing introduced later in the glass-fusion operation; or the lime, limestone or gypsum may be excluded from the roastingoperation and used only in the final fusion of glass. Such variations fall within the generic principle of the process described inmy said co-pending application, which is essentially to roast the-lead sulfid thoroughly mixed with a difiicultly fusible substance, under' test conditions a-s'to purity of the roasted product, and then. to use this roasted product in glass making.

' The lead-containing material orproduct itself resulting from the practice of the process, and hereinafter claimed, possesses great advantages as a means of introducing lead into glass; .l'ts powder is practically without deleterious efl'ect upon the workmen. The product d ssolves in glass without any chenncal decomposition, such as necessarily accompanies'the use of lead sulfate, lead carbonate, or lead sulfid and sodium sulfate; Moreover, I have found that inydcad-cntaining material dissolves quickly and uniformly to a more homogeneous lead glass than can be obtained, so far as I am aWare by the use of any of the lead salts or compounds'zbefore proposed for use inglass making. Having thus described my invention, what Iclaimis:

1. As a' new material foruse in glass .making, the granular, ,si'ntered'product ob- 'tained, by dead roasting, to a percentage of not more than about .05 er cent. of sulfur,

.a mixture of galena anc a substance diflicultly-fusible at the roasting temperature but suitable to the composition of lead glass; substantially as described. I

2. As a new material for use in glass making, agranular substance consisting of fused or sintered lead silicate associated with silica and practically devoid of sulfur; substantially as described.

3. As a new material making, a granular substance consisting of fused or sintered lead silicate associated with silica and a calcium compound and practically devoid of. sulfur; substantially as described. v

4.- As a new material for use in glass making, the product obtained by dead roasting a mixture of lead sulfid and silica until the residual sulfur is not more than about .05 per cent; substantially as described.

5. As a new material for use in glass making, the product obtained by dead roast- -ing a nixture of lead sulfid, silica, and a calcium compound (such as lune, limestone or gypsum) until the residual sulfur is not more than about-'05 per cent substantially as described.

In testimony whereof I aliix my signature, in presence of two witnesses.

EUGENE coaurmus SULLIVAN.

'Witnesses; F 1 JAMES HOARE,

' 'MICHAELJ. MooRE.

for use in glass 

